Here's one that is simple as pie. I've got a Thompson Contender with a Super 14 barrel in 30/30 Win. and also a Super 14 barrel
in 44 Mag. The 30/30 is moderately fun to shoot with ammo loaded with pistol powder, like Reloader 7 and the like, but the
44 mag barrel is not much fun at all. So I figured more is always better and had the chamber on the 44 mag. barrel
deepened to accept 444 Marlin Ammo. Now you got yourself a pistol. Not for the half hearted or weak wristed, but
fun as heck. The cup pressures for the 444 Marlin are pretty much equal to the 30/30 Win, so its a safe weapon to
shoot, if you can hang on to it. Give it a try....It will thrill ya...